1. Technical Field
The present invention relates generally to computer hard drives and more specifically to the interaction of the hard disk with the read/write head.
2. Description of Related Art
Under normal operating conditions, the read/write head of a hard drive does not come into physical contact with the hard disk, but instead rides an air cushion just above the surface of the disk. However, failures can occur, wherein the head come into contact with the disk, resulting in damage to the disk and/or interference with the reading and writing of data. This event is referred to as a head crash or Head-to-Disk Interference (HDI) event. When the read/write head comes in contact with the disk, it can cause extensive loss of data because the magnetic coating on the disk is removed or otherwise made unreadable.
The magnetic debris resulting from head/disk contact is circulated within the head/disk enclosure until it is deposited on an internal drive filter element. If it were possible to detect the beginning of a head crash event early enough it would be possible to mitigate the loss of data before it became catastrophic.
Therefore, it would be desirable to have a method for detecting the beginning of a HDI event and minimizing its effects.
The present invention provides a method for detecting head-to-disk interference events in a disk drive. The invention comprises coupling a transducer to an air filter in the disk drive, wherein the transducer detects changes in magnetic readings due to debris produced by physical contact between a read/write head and a magnetic storage medium (head crash). The recirculation filter is monitored during disk drive operations and comparing magnetic readings from the transducer with defined parameters. If the transducer readings exceed the defined parameters, the spindle motor of the disk drive is shut off, thus stopping the rotation of the disk and minimizing data loss and damage due to the head crash.